Ecohouse a design guide doc

Acknowledgements vii Introduction to the Ecohouse Design Guide 11 The form of the house: the building as an analogy 15 2 The environmental impact of building materials 38 Andre Viljoen a

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First published 2001

Sue Roaf 2001

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British Library Cataloguing in Publication Data

Roaf, Sue

Ecohouse – a design guide

1 Architecture – Environmental aspects

Includes bibliographical references and index.

1 House construction 2 Green products 3 Sustainable development.

4 Architecture and society 5 Dwellings – Energy conservation 6 Housing and health 7 Construction industry – Appropriate technology.

I Title: Ecohouse II Fuentes, Manuel III Thomas, Stephanie IV Title.

Acknowledgements vii Introduction to the Ecohouse Design Guide 1

1 The form of the house: the building as an analogy 15

2 The environmental impact of building materials 38 Andre Viljoen and Katrin Bohn

Christopher Day

6 Health and happiness in the home 123

Case study introduction: towards the new vernacular 239 Owner Place Country Designer/Architect/Team

1 Sue Roaf Oxford UK Sue Roaf and David Woods 242

2 Inglis & Goudsmit Findhorn Scotland Johan Vorster 246

3 Økologiske Hus AS, Marnardal Norway Bjørn Berge, Gaia, Lista AS 251 Norges Forskningstråd,

statens Forurensningstilsyn

4 Krister Wiberg Lund Sweden Krister Wiberg 254

5 Dr and Mrs Ramlal Hyderabad India Prashant Kapoor, Saleem Akhtar, 256

Arun Prasad, Manuel Fuentes

6 Syounai Hamamatsu Japan OM Solar 262

7 Mr and Mrs I Sagara Inagi Tokyo, Japan Ken-ichi Kimura, Mr H Matsuoka 266

8 Jimmy Lim Kuala Lumpur Malaysia Jimmy Lim, CSL Associates 268

9 Ministry of Construction, Surabaya Indonesia Prof Silas, Dr Y Kodama 272 Indonesia

10 F and F Riedweg Townsville Australia Felix Riedweg 275

11 Graham Duncan Waiheke Island New Zealand Graham Duncan 279

CONTENTS

Owner Place Country Designer/Architect/Team

12 Ashok and Rajiv Lall Delhi India Ashok Lall Architects 282

13 M L Bidani Delhi India Arvind Krishan 288

14 Isaac Meir Negev Desert Israel Isaac Meir 291

18 Richard Levine Lexington, KT USA Richard Levine 313

19 Charles Middleton Gravenhurst, Canada Charles Middleton 317

Ontario

20 Christopher Day Pembrokeshire Wales Christopher Day 321

21 David Johnson Monmouth Wales Andrew Yeats, Matthew Hill, 325

The authors would like to thank the following people for their help

in compiling this book:

• for chapters of, and contributors to the book: Christopher Day,Andre Viljoen, Katrin Bohn and Robert and Brenda Vale; for theclimate maps: Cherry Bonaria;

• for illustrations: Tony Garrett, Edward Mazna, Andrew Marsh,Ian Giuliani, Glasshead Films Ltd, and The Centre for Windowand Cladding Technology, Bath, with a special thanks to MichaelHowlett for his beautiful pencil drawings;

• for case studies: all those who have helped to make the studies

so varied and interesting, many many thanks, including Puteri

SC Cempaka for help with locating the Indonesian example;

• for support during the writing of the book: Ana Lopez, RyanRees, Mr Thomas (Stephanie’s father), Christopher and RichardRoaf, and Maita Kessler;

• for contributions to the text: everyone who has helped, ing Fergus Nicol, Steven Szokolay, John Willoughby, DavidWoods, David Olivier, Jeremy Dain, George Goudsmit, AndrewBairstow, Vivien Walker, Michael Humpheys and Ellen Salazar;

includ-• thanks are also due to our many students on the MSc in EnergyEfficient Building at Oxford Brookes University who are justbrilliant Manuel, Stephanie, Cherry, Ellen, Prashant, Valpy,Andrew and Johann have all helped make this book happen, ashave many others along the way Keep up the good work!

• for future contributions: this is very much a work in progress,

so can we thank now all those people who will be kind enough

to send in advice, suggestions, information and corrections to

be included in the next edition of the book;

• thanks to Nat Rea (tel: +44 2076 245063) for his photos of theOxford Ecohouse;

• for Figures 8.12 and 8.13 © Times Newspapers Limited, 27thJanuary 1996

ACKNOWLEDGEMENTS

The first question to answer should be: what is an ecohouse?Eco-architecture sees buildings as part of the larger ecology ofthe planet and the building as part of a living habitat Thiscontrasts with the more common notions of many architects,who see a building as a work of art, perhaps on exhibition in asettlement or as ‘frozen music’ in the people-less pictures ofglossy magazines Some architects see the process of design as

a production line with the building as a product to be deposited

on a site, regardless of its particular environment or qualities Youwill see from the case studies at the end of the book thatecohouses are closely connected to their site, society, climate,region and the planet

Why bother making buildings connect in this way? Because thealternative is not acceptable and ‘modern buildings’ are literallydestroying the planet It does not help that the numbers of people

on the planet are growing so rapidly (5.3 billion in 1990; 8.1 billion

by 2020; 10.7 billion in the 2080s) or that we have increasinglysophisticated technologies to exploit the Earth’s natural resources.But it should be widely known that buildings are the single mostdamaging polluters on the planet, consuming over half of all theenergy used in developed countries and producing over half of allclimate-change gases

The shift towards green design began in the 1970s and was apragmatic response to higher oil prices It was then that the first

of the oil shocks, in 1973, sent fossil fuel prices sky high and the

‘futurologists’ began to look at the life history of fossil fuels on theplanet and make claims about how much oil and gas were left.Their predictions were alarming and, 30 years on, we appear still

to have abundant oil However, their calculations on total reserveswere fairly accurate and many of their predictions have yet to beproved wrong From the features on gas, oil and coal below youcan see that it is now estimated that we have left around 40 yearsINTRODUCTION TO

THE ECOHOUSE DESIGN GUIDE

of conventional oil reserves and 65 years of gas, at current rates

of extraction Recent studies (see Bartsh and Muller, 2000) point

to 2012 as being when the oil shortages will really begin to bite

hard and to start changing the face of society

World oil demand

World crude oil supply Opec Middle East crude oil supply World crude oil supply excluding Opec Middle East

1.

World oil demand and conventional oil supply in millions of barrels per day

(Guardian, 17 June 2000, p 30).

OIL: the estimates of total oil reserves have changed little in

20 years and the last big oil field discovered was in the North Sea

in the 1960s The output from the southern 48 States of America

began to decline in the 1940s The output from oil fields typically

follows a form of bell-shaped curve, rising steeply to a plateau then

falling sharply Every day the world consumes around 70 million

barrels of crude oil To date, we have used around half of the total

estimated oil reserves globally and it is thought that within a few

years we will reach the peak of global oil production, after which

time conventional oil production will decline.

The capacity for exploiting those reserves can be increased by

technologies that allow more of the reserves to be extracted, for

example by using pumped gas and water Thus in the USA, UK and

Norway, for instance, reserves are intensively exploited while in

other areas, such as Saudi Arabia, Kuwait and Iraq, they are not.

The term ‘reserves’ indicates the long-term potential of an oil field

while ‘capacity’ describes what can be pumped from that field

taking into consideration constraints such as the technical efficiency

of the extraction process An increase in the rate of recovery of oil

from a field from 30 per cent to 60 per cent is the equivalent of

doubling the proven recoverable resource.

Perhaps worst hit by the decline in oil reserves will be the fields

in the USA and the North Sea, which will be badly affected by

Introduction to the ecohouse design guide 3

OIL (continued): 2020 Issues of how to sustain current lifestyles in

these regions, with declining oil reserves, unpredictable global oil

prices and geopolitical conditions, should prove very interesting.

There is capacity for considerable expansion in oil production over

the next few years to meet increased global demands from the

various oil producing countries However, the capacity to increase

supplies may well not actually meet the increasing demands The

cost of oil will depend on the match between demand and supply,

the ‘time lag’ between synchronizing these and the size of ‘buffer’

supplies that are currently largely held in the Gulf Prices will rise

when governments perceive a reduction in the size of the buffer,

or anticipate that demands for oil are growing faster than

investment in capacity expansion The oil crises of 1973 and 1979

were caused by such a mismatch of demand and consumption.

Recently the oil price on the global market has fluctuated from

under US$10 a barrel to over US$30 a barrel Our societies are

highly dependent on oil, the price of which has not proven

particularly predictable in the past.

The world does hold huge reserves of non-conventional oil that

will be exploited when the scarcity of conventional reserves pushes

the price of a barrel above $30 for long periods.

When making long-term predictions, analysts have to balance the

capacity, or production, of a field against the size of its reserves

and the onset of ‘oil field decline’ If, as some maintain, global

production will plateau in around 2005 and we continue to increase

our global demand as predicted, there is a strong likelihood of

considerable volatility in oil prices in the future, as happened in the

1970s No one is brave enough to stake their reputations on what

oil will cost in 5, 10, 15 or 20 years but pundits suggest that by

around 2015 global natural decline in conventional oil production will

be noticeable, and may be considerable after around 2020 These

declines can be compensated for by developments in

non-conventional oil production but at a high cost to the consumer One

worry is that old oil fields in areas such as the Middle East and

Venezuela are already showing signs of fatigue and may not yield

their full potential of reserves A rough figure given is that we may

have around 40 years left of conventional oil reserves.

As Bartsch and Muller (2000) state in their recent book Fossil

Fuels in a Changing Climate, ‘It is not that we will not have enough

oil to take us to 2020 but that the road is likely to be bumpy and

subject to a number of economic and political shocks’.

GAS: reserves of natural gas are abundant and current estimates suggest that stocks could last for 65 years at current rates of consumption Some countries rely on gas for over half of all the primary energy they use and the biggest increase in demand is for gas-powered electricity stations Gas is a cleaner fuel for the generation of electricity than coal or oil and results in less CO2emissions per unit of delivered energy generated because gas-fired power stations are more efficient.

Two interesting characteristics of gas are that:

1 it is difficult to move over long distances without leakage and

2 most of it is located in countries where demand for it is lower For instance, in Europe there are around 3.2 trillion (3.2 ⫻10 12 ) cubic metres of proven reserves of natural gas and the

Europeans are consuming around 0.38 trillion cubic metres per year, which gives us at this rate just under 10 years of gas left

in Europe However, more reserves may be found In the USA the situation is more difficult with around 3.2 trillion cubic metres proven reserves left and 0.686 trillion tonnes being consumed a year At this rate the USA has around 5 years of reserves of their own natural gas left However, such countries are very aware of the limitations of their own reserves and import large quantities of cheap gas now, with a view to conserving their own stocks for the future For example if the USA imports three-quarters of the gas they use every year at current rates their own stocks could last for 20 years.

Fortunately there are abundant reserves in other areas of the world

of which 77 per cent are in the Middle East (39 per cent) and North Africa (38 per cent) It is estimated that globally there are reserves that will support demand for gas for the next 60 years at least However, as local reserves of gas are depleted and countries have to buy more and more of their stocks from the global market they will have to pay the global market price The rate of uptake of cleaner gas technologies, used to reduce CO2emissions, for instance, from power stations, will be influenced by the cost of gas, which will increasingly be dictated by the highest bidders Prices will eventually rise significantly in countries where the fuel is now very cheap, such as the USA, but obviously will be less affected in countries such as Denmark where fuel prices have been kept high and energy efficiency is widely practised The USA now consumes around 27 per cent of the world’s gas (with 4 per cent

of the world population) and is responsible for about 23 per cent per year of global gas production.

The oil crisis of the 1970s resulted in the rise of the solar house

movement: homes built to use clean renewable energy from the

sun Two such houses can be seen in the case studies in Kentucky

and Tokyo These houses used passive solar and solar hot water

systems with rock bed and ground storage systems to store heat

between the seasons Such innovative houses provided the

foundations on which were developed the blueprints for the

ecohouses of the twenty-first century

In the 1980s came the next big shock – climate change It was

then that the rates of depletion in the ozone layer and the

increase in greenhouse gases and global warming became

appar-ent The predictions made by the Intergovernmental Panel on

Climate Change in 1990 have been borne out by the steadily

increasing global temperatures over the 1990s, the hottest

decade on record

Just as people dismiss the fossil fuel depletion claims by saying

that ‘they were wrong in the 1970s about oil, you see we have

not run out yet’, so climate change predictions are simplistically

rebuffed with phrases such as ‘the climate of the world has always

changed’ It is obvious from Figure 2 that this is indeed correct,

Introduction to the ecohouse design guide 5

COAL: the main problem with coal is that it is a dirty fuel and

contributes 38 per cent of CO2emissions from commercial fuels

and is also a major source of sulphur dioxide and nitrous oxides

emissions, as well as particulates and other emissions Coal

currently provides only 26 per cent of the world’s primary energy

consumption, very much less than in 1950 when this figure was 59

per cent There are abundant reserves of coal in the ground

estimated to be capable of lasting over 200 years Over 50 per cent

of the reserves are in the USA, China and Russia The coal industry

does have the additional problems of poor working conditions in

some mines and the high costs of transport for the fuel In France

it is expected that all mines will be closed by 2005.

The costs of producing coal vary significantly Internationally

traded coal ranges in delivered price to the European Union (EU) of

between US$30 and US$55 per tonne, which in terms of fuel oil is

roughly equivalent to US$45–75 per tonne This compares with the

average spot price of fuel oil delivered to northwest Europe in 1997

of US$90–95 per tonne and between US$65 and US$70 per tonne

in the first half of 1998 This indicates that coal is very

competitively priced against oil but it does have a high

environmental impact compared with fuel oil (medium impact) and

gas turbines and natural gas combined-cycle power plants (low

impact), which will limit its wider use globally in the future for

environmental reasons.

Climate change over four time scales: a, the last 1 million years; b, the last 10 000 years;

c, the last 1000 years; d, the last 140 years (sources, a–c: Houghton et al.,1990; d: http://www.met-office.gov.uk/sec5/CR_div/CoP5/obs_pred_clim_change.html).

but what is deeply worrying is the revealed rate and scale of

change that is now happening

The main greenhouse gas is CO2 and the main source of CO2

(ca 50 per cent of all man-made emissions) is buildings If we

continue to produce greenhouse gases at current rates of

increase in a ‘business-as-usual fashion’ predictions by the UK

Meteorological Office indicate impacts will be substantial and by

2080 will include:

• a rise in global average temperatures of 3ºC over the 1961–1990

average by 2080;

• substantial dieback of tropical forests and grasslands with

result-ing loss of CO2 sink;

• substantial overall decreases in rainfall amounts in Australia,

India, southern Africa and most of South America, Europe and

the Middle East Increases will be seen in North America, Asia

(particularly central Asia) and central eastern Africa;

• an increase in cereal yields at high and mid-latitudes such as

North America, China, Argentina and much of Europe At the

same time cereal yields in Africa, the Middle East and

particu-larly India will decrease, leading to increases in the risk of famine

in some regions;

• sea levels will be about 40 cm higher than present with an

estimated increase in the annual number of people flooded from

approximately 13 million today to 94 million in 2080 Of this

increase 60 per cent will be in southern Asia, from Pakistan

through India, Sri Lanka, Bangladesh and Burma and 20 per cent

in Southeast Asia from Thailand, Vietnam, Indonesia and the

Philippines Under all scenarios sea level rises will affect coastal

wetlands, low lying islands and coastal lowlands;

• health impacts will be widespread and diverse By the 2080s an

estimated 290 million more people will be at risk from malaria,

with the greatest risk in China and central Asia Fewer people

will die in winter in temperate cities and more will die in summer

from heat-related problems (www.met.office.gov.uk/sec5/

CR_div/CoP5/obs_pred_clim_change.html) Skin cancer rates will

soar In Queensland, where UV-B radiation is the highest, it is

predicted that three out of every four people will get skin cancer

In America, in 1935 the chances of getting skin cancer were 1

in 1500, in 2000 the chances are 1 in 75 (www.geocities.com/

Rainforest/Vines/4030/impacts.html)

There are so many related impacts of greenhouse gas emissions

that we only touch on them here Yet we see them illustrated daily

in newspaper articles on the extinction of species, the increase in

number and intensity of floods and cyclones, water shortages and

Introduction to the ecohouse design guide 7

the starvation that results from droughts What is certain is that

we must act now to reduce CO2 emissions globally and that one

of the most effective sectors from which to achieve rapid tions in emissions is buildings Houses consume around half of allthe energy used in buildings

reduc-A recent Report by the Commission on Environmental Pollution

in the UK states that if we are to begin to attempt to stabilizeclimate change we will have to introduce cuts in all CO2emissions

of around 60 per cent This means using 60 per cent less energy

to run the home (http://www.rcep.org.uk/) This is actually not toodifficult, as demonstrated in many ecohouses For instance, theOxford Ecohouse emits around 140 kg CO2 per year while other,similar sized, houses in Oxford will produce around 6500 kg CO2per year This is because the Oxford Ecohouse is run largely usingrenewable solar energy This demonstrates how important solartechnologies are for the ‘Low Carbon Lifestyle’

But what is the typical architectural response to the challenge ofglobal warming? It is not to make the building do more of the work

in providing better shelter against climate change, nor to use solartechnologies, but to install air-conditioning, which is a key element

in the vicious circle that is creating global warming

Air-conditioning systems represent the greatest source of climatechange gases of any single technology In the USA, which has only

4 per cent of the world’s population and yet produces around

25 per cent of the global CO2annually, over 40 per cent of city generated is used in air-conditioning systems Energyefficiency is absolutely not an issue, in general, with the US archi-tectural profession Indeed, climate change is not an issue in themajority of architectural offices around the world who have

electri-OZONE DEPLETION

GLOBAL WARMING

HIGHERTEMPERATURES

MORE ENERGY USEDMORE GREENHOUSE GAS

EMISSIONSMORE EMISSIONS OF OZONE-DEPLETING CHEMICALS

MOREAIR-CONDITIONING

systematically, over the last 30 years, shut the indoor climate off

from the outdoor climate, so requiring air-conditioning to make the

building habitable Air-conditioning engineers have traditionally

made their profits by putting as much plant as possible into a

build-ing It is not uncommon for heating and ventilating engineers to

insist on having fixed windows throughout a building, not least

because the calculations for system performance are too difficult

if an open-window scenario is adopted So, many buildings have

to be air-conditioned all year round while perhaps for only one, two

or three months is the external climate uncomfortably hot or cold

In addition, many ‘fashionable’ architect-designed buildings contain

excessive glass, overheat, create extreme indoor discomfort and

can only be saved from becoming hellish environments by huge

amounts of air-conditioning plant When sensible engineers

suggest that perhaps the building would be better without, for

instance, the glass roof, architects have been heard to retort that

engineers cannot understand great design ideas and they should

do what they are paid to do and not express opinions about the

building’s aesthetics

The world needs a new profession of ecotects, or archi-neers or

engi-tects, who can design passive buildings that use minimal

energy and what energy they do use comes from renewable

sources if possible It is the only way forward

The scenario for future global energy consumption developed in

the early 1990s by the Shell oil company demonstrates this well

Figure 3 shows how the demand for energy continues to grow

exponentially while conventional fuel sources such as oil and gas

begin to show significant reductions in output The gap is filled by

renewable energies such as wind and photovoltaic (PV, solar

Introduction to the ecohouse design guide 9

Surprise Geoth.

Solar Biomass Wind Nuclear Hydro Gas Oil and NGL Coal Trad Bio.

electric) energy It was on the strength of such predictions thatShell and BP have invested huge amounts of money in the devel-opment of PV production and distribution companies.

By the decisions we make on the drawing boards in ourcomfortable offices the global environment is changed The world

is warming and the ozone layer thinning Some time in the not toodistant future building designers will be made to take into accounttheir own global environmental responsibilities This will be donethrough building regulations, fuel price increases and carbon taxes.The sooner we start to change architecture, from an appearance-driven process to a performance-driven art, the better prepared wewill be to lay the building foundations of the post-fossil-fuel age.The best place to start learning is with an ecohouse

We have tried to bring together ‘How to’ information on keyissues not well covered in other books This includes developingtechnologies, thermal mass, ventilation, cold bridging, materialsissues, passive solar design, photovoltaics, cyclone design andgrey water systems The book is not a comprehensive guide to allaspects of low-energy or ecological building Many subjects havebeen very well covered in other books; for example, passive solardesign (Mazria, 1979; Yannas, 1994), low-energy house design inthe UK (Vale and Vale, 2000), materials (Borer and Harris, 1998;Berge, 2000) and timber-frame houses (Pitts, 1989, 2000; Talbott,1993) We also think that house buyers can choose many elementsfor their house pragmatically, with a little help from their local build-ing supplies store For instance, what is the best glass for theirwindows, based on what is locally available, compared perform-ance data and what they can afford

We do incorporate the wisdom learnt from ecohouses aroundthe world in the Case Study section These are not ordinaryhouses The majority are built by architects for themselves andoften by themselves, not for clients They express, in their variedforms, the local climates, resources, culture and the tastes of theirdesigners, as well as the design ethos of the times in which theywere built

The temptation to ‘innovate’ can often lead us unwittingly intoproblems, but from them we learn For example, the early solarhouses often overheated because, in the rush to utilize free, cleansolar energy, the dangers of the sun were underestimated Thebest modern buildings do have excellent solar control and yet it isastounding to see how many still employ glass roofs and walls thatnot only can cause severe discomfort to people inside but also canresult in huge bills for compensatory cooling systems Somepeople never seem to learn Clients should avoid such designers.Today photovoltaics are already cost-effective in virtually all

countries for off-grid systems In far-sighted countries, such as

Japan and Germany, there are already over 10 000 installed

domes-tic PV systems in use In Britain (where £900 000 000 was spent

on the Millennium dome at Greenwich) there are about ten

installed grid-connected PV systems on houses To adapt an old

Yorkshire expression, some people are ‘all front parlour and no

Sunday lunch’ when it comes to sustainability and sensibly

invest-ing in the future for our children

It is incredible to note that in many parts of the world the

challenges of trying to reduce the catastrophic impacts of buildings

on the environment are still left to individuals, including Britain The

challenges ahead seem so enormous that it is difficult to see what

we, as individuals, can do But it was Confucius who said that if

each person solved the small problems over which they have

control then the larger problems would disappear

Why are such important issues as the impacts of climate change

and fossil fuel depletion ignored by politicians when our species is

so obviously at an ecological watershed? We are only one species

on the planet, yet we are multiplying exponentially, every day we

destroy other species and their ecological niches and, in many

parts of the world, we are even destroying our own peoples and

their habitats This was historically demonstrated on Easter Island

where the population destroyed all the trees on the island and had

to flee to survive, or die This is happening around us today Will

it be obvious to us that we are the cause, when the first of the

Small Islands disappear altogether when sea level rises? Will we

register that fact?

Species can adopt symbiotic, parasitic or predatory lifestyles, and

they can also commit suicide, just as species such as lemmings

do There is potentially much to be learnt about how we can

develop through the study of ecology, by comparing our behaviour

with that of other species on the planet

ECOLOGY is defined as the study of the interactions of

organ-isms and their physical and biological environment Organorgan-isms

have the ability to control the movement of energy and material

between their internal and external environments They adapt in

order to use the water, energy, heat, light and resources available

in different environments and climates to sustain life in the

multi-plicity of ecosystems on the planet

Competition between species is a driving force that can lead to

evolutionary divergence between species, to elimination of species

and also, more positively, to a co-evolution and the development

of mutually supportive relationships Evolution requires adaptation,

not only to adjust to the changing circumstances of climate and

environment, but also to changing populations and resources

Introduction to the ecohouse design guide 11

The theory of evolutionary ecology begins with Charles Darwin

in the late nineteenth century He regarded the environment as thekey agent of ‘selective mortality’ without mentioning the relation-ship of birth rate to the survival of species In 1930 Ronald Fisher’sclassic book The Genetical Theory of Natural Selection, dealt withthe importance of population growth rates but this subject waslargely marginalized until 1966 when the theory of the ‘life histo-ries’ of populations became popular This theory states that adapta-tion is largely the making of compromises in the allocation of timeand energy to competing demands It introduced the idea that verydifferent ‘life history’ adaptations are favoured under conditions ofhigh and low population densities in relation to the carrying capa-city of the environment At high densities, selection favours adapta-tions that enable populations to survive and reproduce with fewresources and hence demands ‘efficiency’ in the way resourcesare used At low densities, adaptations promoting rapid populationincreases are favoured, regardless of efficiency Natural selectionadjusts the amount of time and resources expended not only inaccordance with changes in the environment but also with the lifehistory of a population

So how would this affect us? In times of ecological threat animalspecies respond in a variety of ways, from becoming spiteful tobeing altruistic Ecologists would perhaps expect selfish behaviour

to prevail to the exclusion of altruism because it is the selfishbehaviours that increase the reproductive success of the dominantspecies or individual

Growth, however, is a survival strategy for species with a lifehistory at a low-density phase At high densities, populations mustemploy strategies of efficiency to survive Human beings areunique in the history of the world because of the sheer scale ofthe impacts we have had on the global environment and in partic-ular on the Earth’s atmosphere, and our ability to comprehend, andalter, them

If we are to survive the challenges ahead of us in the first century, with some semblance of normality retained, we willhave to effect fairly radical changes in what we, as individuals,expect from the infrastructures of our own ecological niches, ourhouses and settlements and society To do this we will have tobehave fairly altruistically, not only towards our own families,friends and neighbours but also to the larger family of our fellowhuman beings Altruism is not unknown when bonds of loyalty arestretched to encompass larger and larger groups Humans seldomquestion that, in times of war, they are asked to die for theircountry This they do ultimately to protect their families, throughwhom their genes are perpetuated

twenty-When faced with the twenty-first century challenges it is the

global nature of human being’s environmental impacts that make

it imperative to see our kin as all the people of the world If not,

few of us will survive There are no safe islands in the twenty-first

century Europe knows that if the countries of northern Africa

suffer from repeated severe droughts it is to Europe that the

ravaged populations of these regions will flee The same is true of

America, Mexico and Latin America The history of humans is one

of diasporas, the dispersions of peoples If there are more people

and fewer resources, such movements will surely affect each of

our everyday lives?

Buildings are only part of our habitat Buildings are intimately

linked to the local, regional and global environments that are all

part of our ‘Ecological Niche’ It is the responsibility of our

gener-ation to begin to adapt our buildings to ensure that we can

stabi-lize climate change, that we can live without fossil fuels and that

we do not unsustainably pollute the environment Only by so doing

can we ensure the survival of our own habitats

This cannot be so difficult because people survived on the planet

for millennia without the miracle fuels of oil and gas Traditional

buildings have much to teach us about how to design regionally

appropriate structures

We can change fast enough We can mix the wisdom of the

master builders, new knowledge, materials and renewable

technologies to create ecobuildings, the New Vernacular, to

minimize the environmental impacts of buildings We can now

measure those impacts with the new methodologies for counting

the environmental costs of buildings We do need a new type of

designer, part architect, part engineer, and to get rid of heating and

cooling machines where possible or power them with renewable

energy What you will read in the first section of the book shows

that all of this is possible and, in the second section, that it is

already being done in many of the case study ecohouses from

around the world

Introduction to the ecohouse design guide 13

Twentieth-century architecture was influenced by a single analogy

coined by the great French architect, Le Corbusier He proposed

that ‘the building is a machine for living in’ This is very far from

the truth The mistake, at its heart, is that a machine is an

inani-mate object that can be turned on and off and operates only at the

whim of its controller A building is very different because, although

it is true that it can be controlled by its occupants, the driving force

that acts upon the building to create comfort and shelter is the

climate and its weather, neither of which can be controlled,

predicted or turned on and off

Machines are fixed, static objects, amenable to scientific

assessment Buildings are part of a complex interaction between

people, the buildings themselves, the climate and the

environ-ment The view that buildings are fixed also fits well with certain

types of scientific analysis, of daylight factors, energy flows,

U-values, mechanical ventilation and so on But this mechanistic

view finds the more dynamic parts of the system (temperature,

natural ventilation, passive cooling and all the multitude of

human interactions) very difficult to model and, therefore, to

understand In houses it is often these ‘difficult’ parts of the

system that change a house into a home, and the building into

a delight

Considerations of daylight, energy, thermal insulation and the

use of machinery, of course, cannot be avoided – but because we

can calculate them does not mean that they are our only concern

Figure 1.1 demonstrates, for instance, that buildings have their

own thermal life beyond what we can see If we could see heat,

as the thermal imagining camera does, we would probably treat a

building very differently We would know exactly where we need

to put a bit more insulation or place a sun shade, which sun shade

to use or which corner of the room is cold and needs a little

atten-tion

1 THE FORM OF THE HOUSE: THE BUILDING AS

AN ANALOGY

Thermographic images: a, The Oxford Ecohouse, built in 1994, on an Autumn morning; b, the house next door built

in the 1950s; c, a black umbrella (left) and a white umbrella (right) showing that the black material absorbs radiation and gets hot while the white umbrella reflects the sun from its surface and remains cooler; d, a person opening a window from the inside in the Oxford Ecohouse; e, rods of copper, steel, glass and wood demonstrating that heat is conducted more efficiently in some materials; f the Kakkleoven in the Oxford Ecohouse showing the hot ducts in the high mass stove and the hot metal flue passing into the concrete floor above and heating it locally These images are reproduced with thanks to Glasshead Films Ltd who took the films for Channel 4, and George Jenkinson and Andy Hudson of Oxford Brookes University for their digital re-mastering and transmission of the images (Glasshead Films Ltd).

We have to design for the invisible as well as the visible and so

how is this to be done? Buildings have been traditionally designed

using accepted premises (propositions that are adopted after

reasoning) as well as, of course, on premises (the building and

adjuncts set forth at the beginning of a building deed) Three

prin-ciples on which all building should be based are:

1 design for a climate;

2 design for the environment;

3 design for time, be it day or night, a season or the lifetime of a

building and design a building that will adapt over time

Humans have been building on these premises for millennia and

have evolved house types around the world that are well suited to

particular climates, environments and societies This was done by

learning from experience, and with the benefit of repetitive tools

and processes that help designers and builders through the

complex range of tasks necessary to actually put a building

together

One tool of the imagination that is often used when starting a

design is the analogy An analogy is used where two forms may

not look alike but they function in the same way, just as Le

Corbusier described a building as a ‘machine for living in’ This

book starts by considering building form, on which the most

powerful influence in design should be the climate In this chapter,

analogies are used to demonstrate how different forms can relate

to some of the many different climatic functions of a building The

analogies themselves may seem a little simplistic but you will find

that they change the way you look at buildings To further illustrate

the relationship between buildings and climate, a number of

examples of vernacular buildings are included

Finally, at the end of the chapter, a method for evaluating the

climatic requirements of a building form in a particular climate is

outlined with the Nicol graph This simply shows what the mean

climate of a site is, what the comfort requirements of local people

will be and gives an indication of how much heating and cooling

will be needed to achieve those comfort conditions in that climate

THE THIRD SKIN

Buildings are our third skin To survive we need shelter from the

elements using three skins The first is provided by our own skin,

the second by a layer of clothes and the third is the building In

some climates it is only with all three skins that we can provide

sufficient shelter to survive, in others the first skin is enough The

more extreme the climate, the more we have to rely on the

build-The form of the house: the building as an analogy 17

People typically generate heat, between 70 and 120 watts each according to how much work they are doing Figure 1.1 shows the radiant surface temperatures of a person opening a window This figure shows a thermal image of heat plumes around people, as the heat from our skin warms the air around us it rises, driven by the buoyancy of hot air (Clark,

C and Edholme, D., 1985).

ing to protect us from the elements Just as we take off and put

on clothes as the weather and the climate changes so we can shed

skins

THE HEAT EXCHANGER

The greater the volume of the building the more surface area it

has to lose, or gain, heat from Figure 1.3 shows that different plan

forms can have more or less wall area for the same plan area The

surface area:volume ratio is very important in conserving heat

transfer into and out of a building To conserve heat or cold the

building must be designed with a compact form to reduce the

efficiency of the building as a heat exchanger

A good example of how not to lose heat because of the shape

of a building is given by the ice-house (Figure 1.4) In many

countries of the world, before refrigerators were invented, people

used to store ice that had been harvested in winter from lakes and

ponds in ice-houses When the hot summer months came it was

taken out and used to cool food, drinks and rooms The only way

that ice could be kept so long was to ensure that it had a minimum

surface area:volume ratio to lose heat from Ice-houses were

designed so that as the ice slipped lower down it would retain its

ball-like shape Some ice-houses could store ice for two years

without it melting (Beamon and Roaf, 1990)

The form of the house: the building as an analogy 19

1.3.

Buildings can have very different perimeter:area ratios depending on their plan

form (Krishan, 1995).

In warm or hot countries the building must become a good heat

dissipater Just as people who are hot sprawl out to lose heat, so

buildings sprawl in warm and hot climates In many hot climates

buildings have a high surface area:volume ratio but the walls facing

the sun are protected from direct radiation by verandas, balconies

or wide eaves The shallower floor plan of heat-dissipating

build-ings also promotes easy cross-ventilation of rooms for cooling,

which in compact plan forms is more difficult House forms in such

climates are either long and thin or have a courtyard, or light well,

in the centre of the house, to maximize the building’s wall area

The relationship between ventilation and cooling is dealt with in

Chapter 5

Do not confuse a hot climate, with mean maximum

tempera-tures below 38°C, with a very hot climate, which is even hotter

In the hottest cities of Saudi Arabia, Iraq, India and Yemen, for

instance, houses are very tall with up to seven or eight storeys,

each providing another layer of protection against the sun The

courtyards in the very hottest areas are replaced with light wells

that allow for cross-ventilation and light penetration but are more

1.4.

The ice-house at Hooke, Chailey, Sussex Drawn after a 1776 diagram by William Broderick Thomas This may be the first illustrated cavity brick wall in Britain and here the cavity was used to keep the groundwater away from the ice, rather than for its insulating properties (Beamon and Roaf, 1990).

shaded against the sun overhead The outer walls of such

build-ings are often shaded with shutters, verandas, balconies and

mushrabiyah, or ventilated timber cantilevered windows In such

climates rooms can become vertical or horizontal buffers, as can

shade elements that keep the sun off mass walls that would

trans-port the heat inwards by conduction Figure 1.5 shows how a large

house, a Havelli, is coupled in the upper floors to the air

temper-ature while in the basement room it is coupled thermally to the

more stable ground temperatures

THE TEA COSY

Well-insulated structures are like tea cosies How quickly the tea

cools will depend on how big the pot is, how thick the tea cosy is

and how cold the air is outside it The effectiveness of the

insulated envelope depends on a number of variables, not least the

area of the envelope in relation to the heating requirements of the

occupants in it and the available internal heat sources

For example, take the tent dwellers of the Mongolian steppes

of Siberia to the deserts of Saudi Arabia The Turkoman yurt (Figure

1.6) is a tent built on a framework of bent wood, with a felt cloth

tent, in which ten or more people can live through the freezing

winter months Heavy clothes are worn, even indoors, and a single

central brazier provides heat The yurt is an airtight structure into

which there is very little infiltration of cold air from the driving wind

The area of the whole floor is only in the region of 15–20 m2 so

the body heat of the people in the tent makes up a significant

amount of the heat they need to warm the family

The form of the house: the building as an analogy 21

1.5.

Time lags between indoor and outdoor temperatures in a Havelli in Jaisalmer, India (Matthews, 2000) (South is to the right of this section.)

You would probably not survive a severe Mongolian winter in a

300 m2 gher with one small brazier fire and ten people Insulated

envelope buildings need constant heating, from a heat source or

from other internal gains such as machines and body heat The

yurt works well because its occupants go to bed very early to

conserve heat and light, and sleep at night under thick quilts, often

with more than one to a bed, saving considerably on heating

Considerations of the thermal performance of building envelopes

are covered in Chapter 2

THE GREENHOUSE

Imagine living in a greenhouse There are no climates in which it

would be comfortable Glass lets in light and, with it, heat

Incoming solar radiation heats us to help keep our internal body

temperature at 37°C It can also overheat us Once solar radiation

has passed through glass it hits a surface in the building and is

reflected or re-radiated at a changed wavelength that can no longer

pass, in the same way, back out through the glass, so causing the

inside of the greenhouse to heat up

This is exactly what is happening with the world’s atmosphere

The short-wave radiation can pass through the clear atmosphere

relatively unimpeded But the long-wave terrestrial radiation

emitted by the warm surface of the Earth is partially absorbed by

1.6.

A Yurt of the Turkoman tribe of Iran (Andrews, 1997, drawn by Susan Parker).

a number of the trace gases in the cooler atmosphere above.

Since, on average, the outgoing long-wave radiation balances the

incoming solar radiation, both the atmosphere and the surface will

be warmer than they would be without greenhouse gases

Once inside the atmosphere or the greenhouse, it is difficult for

the radiation to pass back out, and this is why it is fairly pointless

to use internal blinds because, although they shade people from

direct sunlight, the heat cannot escape from the space External

shading would prevent this problem Conversely, greenhouses

become very cold at night, because they lose heat from the

build-ing surface by radiation and eventually become almost as cold as

the outside temperature It would take a fairly brave person to

actually try to live in a ‘transparent’ greenhouse, or suggest to

someone else that they should!

Greenhouses are direct solar gain buildings The ways in which

the sun can be captured and used in such buildings is covered in

a sun shade (Roaf, 1979).

THE IGLOO

An important feature of building design in cold climates is the use

of stratification of room air Hot air rises while cold air sinks This

is taken advantage of in igloos, which provide shelter in perhapsthe most extreme climates on Earth The occupants of igloos live

on a high shelf, to take advantage of the warmest air in the space,while the cold air sinks down and is contained in the lowerentrance area of the building (Figure 1.8)

THE BUILDING AS A BUCKET

Conversely, in hot climates tall rooms mean that the heat and thehot ceiling are far away from the room’s occupants High-levelwindows can allow the heat to escape from the top of the rooms,thus stimulating air flow even on the stillest days that is driven bythe stack effect alone The stack effect is powered by thebuoyancy of air, which depends on the pressure differencebetween cool and warm air (see Chapter 5) This effect (in anupside-down orientation) has been compared to water: if the build-ing is a bucket with holes in, filled with water, the water will drainout of the holes, as will heat out of a building The greater thetemperature difference, the greater the buoyancy effect

This property of warm air, which can be thought of, almost, asupside-down water flowing around a building, can be used tothermally landscape the ceilings of rooms Hot air can bechannelled around ceilings, in ‘banks’ or walls, to form rivers orlakes of heat that can move between areas or rooms within a build-ing This is well illustrated in Figure 1.9

A BRICK IN A STORAGE RADIATOR

In very cold climates the rooms of buildings, just like people,

huddle together to keep warm, often around a central ‘hot core’,

a heat source such as a fire place Figure 1.10 shows a classic

hot-core building from Lativa where an extended warm wall into

the communal room is always a favourite place to sit in winter

The principle is similar to that of a brick in a storage radiator The

heat comes from perhaps a fire or the sun, and is absorbed in the

thermal mass of the building, as it is in a radiator brick Then,

The form of the house: the building as an analogy 25

1.8.

Section through an igloo showing the thermal stratification above the raised

platform on which people live (Cook, 1994).

gradually, that heat is emitted back into the room over time If a

material is highly conductive, such as the copper or steel shown

in Figure 1.1, it will not store the heat If the Kakkleoven in Figure

1.9 was made of steel or iron it would cool down rapidly when

the fire had gone out, unlike the high density concrete stove that

actually stores the heat and will stay warm for up to 14 hours after

the fire has gone out

The performance of the thermal mass in a building is dependent

on many different factors, including its composition, location in

relation to the other building elements and related ventilation

strategies, issues dealt with in later chapters of the book

THE BUILDING AS A ROMAN BATH HOUSE

In Roman bath houses the floors were warmed by an under-floor

heating system called a hypocaust A fire would be lit under the

great basins used to heat the water for the hot baths and the

excess heat from the fire would be ducted under solid floors to heat

the bath house itself So, in such systems, there is a heat source,

thermal mass to store the heat in and regulate its dissipation into

a space, and a system of heat distribution This idea uses a

convec-tive heat transfer medium, air or water, to a radiator that is part of

the building It can be a horizontal hypocaust under a floor or a

verti-cal hypocaust such as a warm wall, column or Kakkleoven

The form of the house: the building as an analogy 27

1.10.

The traditional Nam house of Latvia The Nam is the central masonry room with the kitchen fire and chimney around which are located A, the hall; B, the small chamber; C, the master chamber; and D, the communal and servants room The outer walls of the house are made of horizontal untrimmed logs (after

a drawing by Guntis Plesums in Oliver, 1997, Vol 2, p 1263).

Even in simple village houses there are some very sophisticated

design systems that make our modern Western houses look very

ordinary One of these interesting house forms is found on the

isolated island of Ullungdo, in Korea (Figure 1.11) It has a double

outer-wall construction with the removable outer buffer zone wall,

the ‘u-de-gi’ (a thatched wall), added to provide protection against

the driving winds of the island The two central winter rooms are

made of log and clay with high thermal performance and good

1.11.

Tu-mak-gyp house on the remote Korean island of Ullungdo with a horizontal hypocaust under the floor of the central room.

1.12.

Sketch section of the Kakkleoven illustrated in Figure 1.1.f that acts like a vertical hypocaust The oven not only heats the surfaces it can ‘see’ radiantly but the hot air rising convectively around it collects under the ceiling, so heating the concrete floor above The flue passes up through the concrete wall above and heats the adjacent sections of the wall by conduction.

humidity control The thick thatched roof provides protection

against the winter snow and summer sun The really clever trick

is the kitchen flue, which is funnelled under the winter living room

to optimize the value of the scarce fuel resources to the

inhabi-tants by being used both for the cooking and the heating While

the mean external temperature measured was 1.2°C, the mean

temperature in the Chukdam buffer space was 1.1°C and in the

internal room it was a comfortable 15.6°C, with a mean relative

humidity (RH) of 44.9 per cent against the external RH of 71.2 per

cent The average floor-surface temperature was 22°C This

demonstrates the excellent ability of the earth walls to control the

RH in a space, in a ‘breathing wall’ (Lee et al., 1994)

THE BUILDING AS A PERISCOPE

Buildings can be periscopes, trained to catch the light, a view, the

wind or the sun If you design them for any of these functions they

must face in the correct direction One of the pioneers of passive

building design said that there are three important factors for

passive buildings: 1 orientation, 2 orientation and 3 orientation

(Docherty and Szokolay, 1999, p 39)

Outside the tropics the best orientation for solar gain, for light

and heat, is towards the equator In the tropics it is best to hide

from the sun under a large hat or a roof If a building faces 15° to

the east or west of the solar orientation it will make very little

difference to the amount of energy that can be garnered from the

sun Simply by facing the living rooms of a house towards the sun

it is possible to save up to 30 per cent on the annual heating bills

of a typical house in a temperate climate Passive solar design is

dealt with in Chapter 7 and is often described in terms of ideal

sites Even in the most difficult sites, with careful thought and

sometimes inspired design, as we see in Figure 1.13, it is

poss-ible to capture the light and heat of the sun Even if the site has

a difficult orientation it is possible to catch the sun with the use

of periscopes projecting from the building in the form of

upper-floor clerestory windows, bay and dormer windows and roof lights

The most difficult orientation is west, because the low western

sun coincides with the hottest time of day (mid-afternoon), making

overheating of west-facing spaces a probability in summer, except

in the high latitudes A western orientation should be avoided if

possible, particularly with sun spaces, because of their potential for

overheating Care should be taken to think about what each room

in a house will be used for and what type of light and heat it will

require from the sun For instance, it would be best to give a

break-fast room access to eastern, morning, sun Perhaps proper dining

The form of the house: the building as an analogy 29

rooms may be good rooms for evening sun A little well-designed

light will give more pleasure to the building users than too much

A TREE IN THE BREEZE

How lovely, on a warm day to sit beneath a shady tree, in a gentle

breeze A building can be like a tree When the temperature of the

air is close enough to local comfort temperatures then, simply by

opening up the walls of a building, its occupants can be adequately

warmed or cooled in a cross-draught This is well demonstrated in

the Queensland case study where, in the tropical climate, set

within the rustling eucalyptus trees, being indoors is as

comfort-able on a hot day as sitting under a tree in the breeze In some

climates the breeze may be comfortable day and night In most

climates the air temperatures at night are too low for comfort

Many people around the world sleep out at night, in the garden,

on the roof or in open-sided buildings or tents, in sight of the stars

1.13.

Professor Georg Reinberg’s solar development in Sagedergasse, Vienna, making imaginative use of the building form to optimize the solar potential of the site (Reinberg, 1996).

A COOL-CORE BUILDING

Just as the ice-houses used to store cold from the winter months

for use in the ‘salad’ days of summer, the thermal mass of a

build-ing can be used to store the cool of the night winds to lower

inter-nal temperatures during the day This is well demonstrated in

Jimmy Lim’s case study where he has built a modern version of

a traditional Malaysian house, with its verandas and balconies

around the high-mass core of a pre-existing building The thermal

mass of the inner walls is completely shaded all year and cooled

by the air movement over them at night (Figure 1.14) This is a

good example of a cool-core building It is simple and works well

and, in fact, could be compared to the old colonial bungalows with

their surrounding verandas

The form of the house: the building as an analogy 31

1.14.

The introduction of a cool core of well-ventilated, shaded, masonry into a

traditional Malay house would have advantages in keeping people in the centre

of the house cooler on the hottest days.

AN AIR LOCK IN A SPACE SHIP TO KEEP THE COLD OUT

In temperate or cold regions all outer doors should have a bufferspace, or air lock This acts in five ways:

1 to keep the wind away from the door and the biting draughtsout of the house;

2 to modify the air temperature, rather as in an air lock, where theair in the buffer space is usually somewhere half way betweeninside and outside temperature This is excellent air to use toventilate the house inside in winter as it is not freezing Small,openable, windows should be built between the buffer porch orsunspace and the house to provide natural pre-heat ventilation;

3 as a place to leave wet clothes outside the house so removingmoisture from inside;

4 as a security and privacy feature so people can be heard or seenbefore they enter the house;

5 to protect the floor construction around the inside of the mainhouse door from becoming too cold In houses without bufferspaces, every time the door opens and cold air comes into thehouse, heat is drawn out of the floor and walls next to the door.The floor is often constructed with a slab of concrete, makingthe floor area around the door much cooler than it would be ifthe door had a porch (Thomas and Rees,1999)

THE COST OF ‘FORM’ IN SITE PLANNING

An interesting case study of a new ecohousing development inHungary demonstrates that there are very real financial advan-tages of adopting solar strategies in housing layout The devel-opers, Aldino Ltd of Budapest, bought a 64-ha site atVeresegyhaz some 30 minutes from the centre of Budapest, inApril 1993 The land had few trees and sloped gently to thesouth The first design (Figure 1.15A) using conventional housinglayouts planned for a maximum density of 380 houses on

1000 m2

plots, but was found to be of too high density and notsuitable, both for social reasons and for the unfavourableeconomic returns offered by the development The second planfor 330 houses was developed along similar lines but the cost ofthe infrastructure and services, which had to be brought from thenearby village half a kilometre away, was found to be double theprice of the land acquisition, and therefore that plan was also notfeasible

Some three years later it was decided to re-evaluate the opment potential of the site and a third scheme for 300 houses

devel-The form of the house: the building as an analogy 33

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1999 layout with 140 houses that proved significantly more cost-effective, owing to the lower infrastructure costs of the development (Charles Cook of Aldino Ltd).

A

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C